WASHINGTON (CNN) -- Scientists involved in the uproar over
experimental cancer drugs tried to downplay the excitement
Wednesday, and one claimed he was misquoted as saying cancer
would be cured in two years.

Nobel laureate Dr. James Watson made public a letter to The
New York Times, which sparked the frenzy with its story
Sunday about the drugs angiostatin and endostatin. In the
letter, Watson denies making the highly optimistic comments
that the story attributed to him.

The Times report that the drugs had starved cancers in mice
by cutting the blood supply to the tumors has set off an
avalanche of media and public interest.

The article, by health writer Gina Kolata, quoted Watson, who
won the Nobel Prize for helping discover the double helix
structure of DNA, as saying Dr. Jonah Folkman "is going to
cure cancer in two years."

Folkman of Harvard University and Children's Hospital in
Boston, developed the two drugs.

But Watson, who directs the Cold Spring Harbor Laboratory on
New York state's Long Island, said he had been misquoted. In
a letter to the newspaper, a copy of which was sent to
Reuters, he wrote:

"Ms. Kolata reported that I predicted that Judah Folkman
would cure cancer in two years. My recollection of the
conversation to which she refers, however, is quite
different.

"What I told Ms. Kolata at a dinner party six weeks ago was
that endostatin should be in ... clinical trials by the end
of this year, and that we would know about one year after
that whether they were effective."

Watson's spokeswoman Wendy Goldstein said Watson feels very
strongly about setting the record straight.

"He did not make such a statement," she said, adding that
Watson felt the newspaper's version of what he had said
"offered what could very well prove to be false hope to a
great many people."

After the article appeared, calls poured in to EntreMed, the
company that makes the drugs; to the National Cancer
Institute; and to Folkman.

Folkman canceled a planned appearance at a prostate cancer
seminar Wednesday when he learned television cameras would be
there. And he told the Boston Globe that people misunderstood
what role angiostatin and endostatin might play in the battle
against cancer.

"However they will be used, they will be added to
chemotherapy and radiotherapy and gene therapy and
immunotherapy and vaccine therapy," Folkman said.

He also emphasized that the drugs had worked only in mice.
"It's got a ways to go in people," he said, "but there is
hope to get there."

Dr. Ted Gansler of the American Cancer Society said the
impact of the story showed how desperate victims were.

"One problem is this impatience, which of course is
understandable in that many, many people are in an urgent
situation now," he said.

Other companies and researchers working on cancer drugs
complained about the coverage that angiostatin and endostatin
got for EntreMed, which has taken a dizzying ride on the
stock market since the article was published.

"The fact that (they) were reported as a miracle cure, and
we're going to cure cancer in the next couple of years was a
tremendous overstatement," said Dr. Lee Rosen, a cancer
researcher at the University of California in Los Angeles.

Rosen has progressed to the human testing of another drug
similar to angiostatin and endostatin called SU5416, which
was developed by Sugen Inc. of Redwood City, California.

Rosen said patients should be wary of cancer cures in mice,
which are much easier to treat than humans, but admitted he
is "very excited" about SU5416.

Angiostatin, endostatin and SU5416 are among more than 300
new cancer treatments undergoing clinical tests.

According to the Pharmaceutical Research and Manufacturers of
America, it takes about 15 years to bring an experimental
drug out of the lab for use with human patients.

Only one in 1,000 compounds tested makes it into clinical
safety trials in humans, and only one in 20 of these are
eventually approved by the Food and Drug Administration
(FDA).

Magainin Pharmaceuticals Inc. of Pennsylvania has a
promising compound, squalamine, in Phase I safety trials in
human volunteers. Derived from shark tissue, squalamine is
an inhibitor of angiogenesis, as are endostatin and
angiostatin. Angiogenesis inhibitors prevent blood from
reaching tumors, killing the tumors.

Agouron of La Jolla, California, has started Phase II and
III safety and efficacy trials of its AG3340 compound,
another drug that blocks blood vessel formation and which
patients could take as a pill.

Boston Life Sciences is testing Troponin I, which is
derived from human cells, and Ilex Oncology Inc. has a
"tumor-homing peptide" that is linked to the anti-cancer drug
doxorubicin in a compound called THP-dox. The company says
THP-dox seeks out and destroys developing blood vessels in
tumors.

Combretastatin. a synthetic derivative of African bush
willow developed by Bob Pettit of Arizona State University,
is about to be tested in the United States and Britain. In
animals, it has killed up to 95 percent of solid tumor cells
by starving them of their blood supply. It is licensed to
Oxigene, a Swedish medical technology company.

The John Wayne Cancer Institute in Los Angeles is preparing
to start Phase III clinical trials -- the last stage before
seeking FDA approval -- of a vaccine against melanoma, the
deadly form of skin cancer.

Dozens of other laboratories are looking at gene therapy,
aimed at replacing the faulty genes that can lead to cancer.

Conventional treatment has become better, too. Among
recent advances are light-activated drugs that can kill
tumors without hurting healthy surrounding tissue, targeted
radiation therapy and antibodies that carry drugs straight to
a tumor.

Survival rates have risen. In the 1930s, according to the
Pharmaceutical Research and Manufacturers of America, only
one in four patients lived for five years after being
diagnosed with cancer.

Now, 97 percent of women with breast cancer that has not
spread live for five years or more, 80 percent of children
with acute lymphocytic leukemia live, and 87 percent of
prostate cancer patients survive.